BRI-Arrowhead, Stock-VTOL-SSTO-Spaceplane

[Broco]

After some real hard trial and error sessions I finally managed to build a pure stock SSTO-Spaceplane with VTOL capabilities without any moving parts (aka no fancy docking port action): The BRI-Arrowhead!

Action groups:

1: RAPIER-engines toggle

2: RAPIER-engines mode toggle

3: Supersonic intakes toggle

4: VTOL-engines toggle

5: Whiplash engine toggle

6: Subsonic intakes toggle

 

Flight profile:

• activate SAS (T) and go to full throttle
• activate VTOL-engines (4)
• it takes some time for the engines to spin up, be patient
• activate the main engines (1 + 5)
• climb at an angle of ~15° (prograde marker)
• once you reach 400m/s speed, shut down the VTOL engines (4) and close the subsonic intakes (6)
• once you reach 10000m, change your angle to ~5° and gain speed. Once you reach 1200+ m/s, climb again at ~15° (prograde marker)
• switch to closed cycle after you reach 22000+ m
• deactivate Whiplash engines (5) and close supersonic intakes (3)
• once you reach 31 km, set autopilot to prograde marker
• cut engines once your apoapsis is above 100km
• at apoapsis, circularize your orbit

 

 

More Images (sorry about that, couldn't imbed the album here, so I just post a link:)

Arrowhead - Imgur

Craft-File:

BRI-ArrowheadVTOL.craft

 

Edited August 2, 2016 by Broco
Adding images + craft

[Majorjim!]

Looks awesome! Any more pics?

[Unknown_Enemy]

nice

any craft file ?

[Broco]

On 28.7.2016 at 4:23 PM, Majorjim said:

Looks awesome! Any more pics?

Sorry about that, couldn't embed the Imgur album like before, I just put down a link to the album now. And sorry it took so long, was busy.

On 28.7.2016 at 7:17 PM, Unknown_Enemy said:

nice

any craft file ?

Ye sorry, forgot about that, I added it now.

Please note, you just get it into orbit of Kerbin, you need to refuel it or drag it to another planet. I built it mainly to fly around Laythe, due to the lower atmosphere and less gravity it's way easier to fly there and rendezvous in space to refuel.

+ For fun of course

[qzgy]

Looks very nice! I'm curious, what did previous attempts look like?

[Broco]

3 minutes ago, qzgy said:

Looks very nice! I'm curious, what did previous attempts look like?

Thank you.

Well, I tried a lot of different setups, what you see here is the end of a 3 day long trial and error run. Basically I started with the design generally set up, since I built a lot of spaceplanes before. But having a spaceplane being able to carry all that additional weight, while being flight stable, having no flameouts and be able to lift the entire craft just with VTOL required a LOT of tweaking. I had to play with different intakes, different fuel tanks, realign engines etc. until I had a craft that was able to lift off barely with just VTOL engines and make it into orbit. Dealing with flameouts was also a huge issue, since when you fly vertically you don't gain intake air.

One older version is this one but it didn't make it into orbit but was easier to fly at Kerbin:

But then again: Too many intakes, too much drag, not enough rocket fuel to make the final burn.

One hint I can give anyone who tries to make VTOLS though: create one section in your craft that holds all main VTOL engines in a line so you can realign them without having to fine tune every single engine every time your center of mass moves due to changes to the craft, just move the whole engine set into the center of mass.

[X-SR71]

Looks cool! Hey does closing the intakes do anything (for the aerodynamic model)?

Edited August 2, 2016 by X-SR71

[Broco]

14 minutes ago, X-SR71 said:

Looks cool! Hey does closing the intakes do anything (for the aerodynamic model)?

Not yet, but in my opinion it should and it was meant to be implemented so that as soon as you close them you reduce drag. Before 1.0 it was the case but the aerodynamic model got changed a lot so that for example angle of attack now plays a huge role. Intakes should have a little bit less drag once they are closed that's why this function was implemented in the first place. I think it just takes some development time to adapt it to the new aerodynamics model.

I'm a programmer so when I design something I plan for it to work in coming patches

In theory this craft should work even better once closing intakes reduces drag unless they take the opposite approach and increase drag on open intakes.

Edited August 2, 2016 by Broco